Inheritance and Selection

In Respiration cells release energy from glucose combining it with Oxygen. This Oxygen is carried to cells by the bloodstream which pick it up in the lungs...

Breathing constantly 'freshen up' the air inside your lungs, replacing the Oxygen which has been taken up by the blood. The chest wall is raised and lowered by the rib muscles, so that it acts like a pump taking air into and out of the lungs.

Cleaning up the air

Specialised cells line all of the RS, some produce mucus, while others have hairs called cilia which beat the mucus upward to the mouth.

This mucus traps dust and microbes which get pushed out of the lungs and swallowed.

Sometimes when you have a cold you produce too much mucus and have to cough to 'clear your chest'.

Effects of smoking

If the ingredients of cigarette smoke are 'sucked' through cotton wool you will see a brown tarry deposit build up. It smells awful and has shocking effects on the human body.

Cilia stop 'beating' because of the tar, causing mucus to build up.

Constant coughing due to build up of mucus damages the air sacs. This is called Emphysema.